基于BC-MIG焊的铝/钢异种金属增材制造工艺

以2 mm厚Q235镀锌钢板为基板,直径1.2 mm的4043铝合金焊丝为增材材料,利用BC-MIG焊工艺进行增材试验,得到了成形美观,性能优良的T型材结构. 采用金相显微镜、显微硬度仪、万能拉伸试验机对接头的组织形貌、硬度分布、剪切性能进行研究,获得了沉积层的组织和力学性能的变化规律. 结果表明,沉积层最底部靠铝一侧和靠钢一侧分别形成细长针状和带状Fe/Al化合物,沉积层中部由向上生长的树枝晶组成,而在沉积层顶部的组织没有定向生长的趋势. 剪切试验表明,铝/钢异种金属T型材最大可承受2 108 N的剪切力,剪切角达到13.5°时,受力一侧堆焊层根部发生断裂,堆焊层上无明显裂纹.

Additive manufacturing process of aluminum/steel dissimilar metal based on BC-MIG welding

To implement additive manufacturing aluminum/steel dissimilar metals, bypass-current MIG welding technology was conducted with 2 mm thick Q235 galvanized steel and 4043 aluminum filler wire with diameter of 1.2 mm. The T-shaped structure with uniform appearance and excellent performance was obtained. The microstructure, hardness distribution and shear property of the joint were investigated respectively through metalloscope, micro hardness test, universal tensile test machine. The variations of microstructure and mechanical properties of the deposited layer were studied. The results indicated that the bottom of deposited layer on the aluminum side and steel side was composed of thin needles and strip Fe/Al compounds, respectively. The middle of the deposited layer is dendrite structure, and the microstructure at the top of the deposited layer does not show any directional trend growth. The shear tests showed that the maximum shear force of T-shaped structure is 2 108 N. When the shear angle exceeds 13.5 °, the fracture occurs at the roots of the T-shaped structure, and there is no obvious crack in the deposited layer.